Noting that rats withdrawn from chronic ethanol drinking have hyperalgesia, Jing Li, Ph.D., from the New Jersey Medical School in Newark, and colleagues trained rats to drink 20 percent ethanol in a two-bottle free choice protocol. When they had a stable ethanol intake, paw withdrawal latencies (PWL) to radiant heat stimulation were compared with and without EA at the acupoint Zusanli (ST36).

The researchers found that, compared with ethanol naive rats, PWL was significantly shorter at 24, 48, and 72 hours, and at seven days after ethanol withdrawal. Compared with sham, one-time administration of EA for 20 minutes at ST36 significantly increased PWL at 24 hours after ethanol withdrawal. Bilateral intra-habenula infusion of the MOR antagonist naltrexone was associated with significant attenuation of the effect of EA.

"These results suggest that hyperalgesia during ethanol withdrawal could be mitigated by EA through a mechanism involving MORs in the habenula, and that EA could be a potential therapy for hyperalgesia in alcoholics," the authors write.